There are some simple basic machines like brother and white. You could check them out I don't know the size of your lettering. Your best best is to check out the lettler sizing and number sizing to see if it meets your needs.

Check out the Janome MC300e. It is an embroidery only machine which comes with two hoop sizes and you have the option of purchasing additional hoops including one that embroiders on hats. The ranges of the hoops go from 2 x 2 inches to 7 x 9 inches. The machine does lettering and numbers in several different sizes and fonts including the ability to download anything from the computer with an ATA card you plug into the machine. If you decide to go with this machine make sure the dealer updates the software to the latest version that will accept the largest hoop size (GigaHoop). These machines retail at $1400, so depending on your dealer I'm sure you can get it for below retail price.

http://janome.com/product_show.php?id=436

If you haven't purchased your machine yet, check out (free) the consumers report magazine website for their sewing machine ratings. I just printed it out a few nights ago and it's great.

Here is a link that might be useful: consumer reports sewing machine ratings